<!DOCTYPE html>
<html lang='en'>

<head>
    <meta charset='UTF-8'>
    <meta name='viewport' content='width=device-width, initial-scale=1.0'>
    <title>Document</title>
    <script src='./vue.js'></script>
</head>

<body>
    <div id='app'>

        <h1>
            <button @click="num1++">{{num1}}</button>
            +
            <button v-on:click="num2+=2">{{num2}}</button>
            =
            {{num1 + num2}}
        </h1>

    </div>
</body>
<script>
    const app = {
        data() {
            return {
                num1: 1,
                num2: 2
            }
        },
        methods: {},
    }
    const vm = Vue.createApp(app).mount('#app')
</script>

</html>